Acoustic Resonance Spectroscopy Research Articles

Differential Acoustic Resonance Spectroscopy for the acoustic measurement of small and irregular samples in the low frequency range

Differential Acoustic Resonance Spectroscopy (DARS) has been developed to investigate the acoustic properties of samples in the kilohertz frequency range. This new laboratory measurement technique examines the change in resonant frequencies of a cavity perturbed by the introduction of a small test sample. The resonant frequency shift between the empty and sample‐loaded cavity is used to estimate the acoustic properties of the loaded sample. This paper presents a DARS perturbation formula that combines a theoretical derivation with numerical simulation and laboratory measurements. Furthermore, a semi‐empirical calibration technique is proposed to estimate the acoustic properties of a test sample. This research demonstrates the potential of the DARS measurement technique for estimating the acoustic properties of acoustically small and/or irregularly shaped samples.

Acoustoelastic effects on the resonance frequencies of prestressed concrete beams—Short-term measurements

In this study resonant acoustic spectroscopy was applied during static loading and unloading of three prestressed concrete beams in the context of acoustoelasticity. At each load step multiple modes of vibration were measured using an accelerometer and a small impact source. It was found that the measured resonance frequencies increased with increasing compressive stress in a manner which can be predicted using a non-linear finite element model based on Murnaghan's third order elastic theory. Previous results from experimental studies on concrete bridges indicate that measured structural resonance frequencies increase with increasing prestress forces. These results have been difficult to explain theoretically and the results from this study can possibly provide a new theoretical basis for the observed stress dependency of the resonance frequencies of concrete structures. Furthermore, the results indicate that a change in the state of stress in a concrete structure can be detected or monitored by measuring one or several resonance frequencies.

Imaging and Elastometry of Blood Clots Using Magnetomotive Optical Coherence Tomography and Labeled Platelets

Improved methods for imaging and assessment of vascular defects are needed for directing treatment of cardiovascular pathologies. In this paper, we employ magnetomotive optical coherence tomography (MMOCT) as a platform both to detect and to measure the elasticity of blood clots. Detection is enabled through the use of rehydrated, lyophilized platelets loaded with superparamagnetic iron oxides (SPIO-RL platelets) that are functional infusion agents that adhere to sites of vascular endothelial damage. Evidence suggests that the sensitivity for detection is improved over threefold by magnetic interactions between SPIOs inside RL platelets. Using the same MMOCT system, we show how elastometry of simulated clots, using resonant acoustic spectroscopy, is correlated with the fibrin content of the clot. Both methods are based upon magnetic actuation and phase-sensitive optical monitoring of nanoscale displacements using MMOCT, underscoring its utility as a broad-based platform to detect and measure the molecular structure and composition of blood clots.

J042033 音響共鳴現象を利用した塗膜厚さ測定のための超音波探触子の選定について

Thicknesses of both side coatings on a steel plate are measured by means of acoustic resonant spectroscopy. Focused and non-focused ultrasonic transducers are employed in this study, and effect of acoustic focusing on the accuracy of thickness measurements is investigated. Focused ultrasonic transducer is useful for measuring the thickness of coating at the local area. On the other hand, non-focused ultrasonic transducer enables us to realize the simultaneous measurement of coating thickness at both sides.

PS29 音響共鳴現象を利用した鋼板塗膜の音響物性値取得と膜厚分布イメージング

In this research, a technique for characterizing thin coating on steel plate and imaging the distribution of coating thickness by utilizing acoustic resonant phenomenon is reported. First, acoustic properties (acoustic impedance, sound velocity and density) of thin coating were measured by the acoustic resonant spectroscopy technique. Using the measured sound velocity of the coating, the thickness distribution of the back side coating of the sample was successfully obtained by scanning the focused-type ultrasonic transducer.

Characterization of ASR damage in concrete using nonlinear impact resonance acoustic spectroscopy technique

This research reports on a successful application of the nonlinear impact resonance acoustic spectroscopy (NIRAS) technique for the characterization of progressive damage in standard concrete specimens. Damage in the specimens is introduced, following ASTM C 1293 testing procedures, through the deleterious alkali–silica reaction (ASR), which leads to the formation of a gel-like reaction product, microcracks, and interfacial debonding between cement and aggregate phases. The microcracks and debonded interfaces act to increase the nonlinearity of concrete. The response of the specimen to impact loading is analyzed to obtain a nonlinearity parameter, which is used as a measure of damage. Measurements are performed on concrete prisms undergoing the ASTM C 1293 expansion test; three aggregates with varying reactivity are examined. The results from the expansion test are compared with those from the NIRAS measurements. For potentially reactive aggregate, the NIRAS technique offers a more definitive assessment of the damage state of the specimen and can be used to distinguish marginally reactive aggregates. The NIRAS results not only demonstrate a clear distinction between nonreactive and reactive aggregates using the nonlinearity parameter, but also the capability to quantitatively track ASR-induced damage in concrete, potentially forming the foundation for field assessment and monitoring.

J042033 音響共鳴現象を利用した両面塗装鋼板の高精度塗膜厚さ測定([J04203]超音波計測・解析法の新展開(3))

This paper describes a technique for measuring the thickness of coating on the double-sided coating steel plates by means of acoustic resonant spectroscopy. The both sides of the samples were covered with coatings of epoxy resin, and the thickness of the coatings was from 10 to 40pm. The acoustic resonance related with the top and bottom coatings of all samples were observed by the 100MHz focused ultrasonic transducer, and the thickness of coatings on both side of the plates were successfully evaluated from their resonant frequencies.

Application of resonant acoustic spectroscopy to beam shaped asphalt concrete samples.

The dynamic modulus of asphalt concrete is a key parameter needed in modern pavement design and management. Traditional laboratory tests based on cyclic loading (0.1–25 Hz) at different testing temperatures are time consuming and require expensive equipment. There is therefore a need for more efficient non‐destructive methods to determine the dynamic modulus of asphalt concrete. This study applies resonant acoustic spectroscopy (RAS) to beam shaped asphalt concrete samples. Multiple modes of vibration are measured at each testing temperature using a miniature accelerometer and a small steel sphere as impact source. The complex modulus from each resonant frequency is calculated using the Rayleigh–Ritz method. The heterogeneous and viscoelastic nature of asphalt concrete presents challenges to the application of conventional RAS. The number of measurable modes decreases with increasing test temperature. In an attempt to extend the usable frequency and temperature range measured, transfer functions are inverted using the finite element method along with a frequency dependent complex modulus. Initial results indicate that RAS can be an efficient method for the prediction of the high‐frequency part of the asphalt concrete dynamic modulus mastercurve.

Resonant acoustic spectroscopy of the fluid saturation effects in a carbonate rock.

We present the results of the acoustic spectroscopy of a carbonate sedimentary rock under various saturation degrees. The data for the same sample were obtained both for elasticity and dissipation tensors within the 2‐octaves frequency range. High accuracy of acoustic measurements allowed distinguishing all three stages in the saturation process: condensation, meniscus creation, and filling the pore space with fluid. Both dry rock parameters and the variations observed are in a good agreement with standard granulometry and chemical analysis. Simple estimations of the relative changes in elastic moduli enable clear explanations of these changes observed. The alteration in the frequency dependence of attenuation coefficient allowed proposing reasonable dissipation mechanisms in porous media that can also be useful in the acoustics of ocean sediments.

On the correlation between the acoustic anisotropy and the magnetic susceptibility anisotropy of the rocks.

Using resonant acoustic spectroscopy technique, we studied several rock samples. Acoustic data were compared with the data for magnetic susceptibility of the same samples. The correlation between the acoustic anisotropy and the magnetic susceptibility anisotropy has been revealed for samples of metamorphic and sedimentary rocks. The existence of this correlation points to the same origin for both magnetic and acoustic anisotropy. The origin is the rock texture created during long tectonic history of the rock samples analyzed. The value of acoustic anisotropy allows evaluating the rock fracturing or the amplitude of tectonic stresses. Under additional calibration, it makes possible the use of the magnetic susceptibility value as a measure of tectonic processes intensity. The latter can be very useful to create express diagnostics of tectonic history in the field conditions.

Acoustic Measurement of a Small Sample Using Differential Acoustic Resonance Spectroscopy

A new acoustic method of estimating property in rocks is presented. This method, called Differential Acoustic Resonance Spectroscopy or DARS, is based on measureing the changes in resonces of a cavity that is perturbed by the introduction of the sample. The change in the resonant frequency is used to characterize the velocity and acoustic properties of the rock sample. This article developed the numerical Differential Acoustic Resonance Spectroscopy simulation using the finite element (FE) method in COMSOL.

A transient method for measuring the gas volume fraction in a mixed gas-liquid flow using acoustic resonance spectroscopy

In this paper, the feasibility of measuring the gas volume fraction in a mixed gas-liquid flow by using an acoustic resonant spectroscopy (ARS) method in a transient way is studied theoretically and experimentally. Firstly, the effects of sizes and locations of a single air bubble in a cylindrical cavity with two open ends on resonant frequencies are investigated numerically. Then, a transient measurement system for ARS is established, and the trends of the resonant frequencies (RFs) and resonant amplitudes (RAs) in the cylindrical cavity with gas flux inside are investigated experimentally. The measurement results by the proposed transient method are compared with those by steady-state ones and numerical ones. The numerical results show that the RFs of the cavity are highly sensitive to the volume of the single air bubble. A tiny bubble volume perturbation may cause a prominent RF shift even though the volume of the air bubble is smaller than 0.1% of that of the cavity. When the small air bubble moves, the RF shift will change and reach its maximum value as it is located at the middle of the cavity. As the gas volume fraction of the two-phase flow is low, both the RFs and RAs from the measurement results decrease dramatically with the increasing gas volume, and this decreasing trend gradually becomes even as the gas volume fraction increases further. These experimental results agree with the theoretical ones qualitatively. In addition, the transient method for ARS is more suitable for measuring the gas volume fraction with randomness and instantaneity than the steady-state one, because the latter could not reflect the random and instant characteristics of the mixed fluid due to the time consumption for frequency sweeping. This study will play a very important role in the quantitative measurement of the gas volume fraction of multiphase flows.

Kinetics of the acoustic resonances in nonlinear-optical crystals during the interaction with the single-mode high-power laser radiation

Resonant acoustic spectroscopy is applied for determination of KTP crystal optical absorption coefficient α at the λ=1.064 μm. Kinetics of the KTP crystal different resonant acoustical modes under high-power laser radiation influence were measured. We suppose that the discrepancy α values obtained is due to acoustical resonances sensitivity to inhomogeneous heating. Resonant acoustic spectroscopy can probably enable a determination of the inhomogeneous crystal temperature distribution.

Resonant acoustic spectroscopy of the interaction of the single-mode high-power laser radiation with crystals

Resonant acoustic spectroscopy technique gives the opportunity to measure the crystal temperature during linear and nonlinear interaction of the laser radiation with crystals. It is based on the registration of the crystal piezoelectric or acoustical resonance frequency change caused by the interaction of the laser radiation with crystals. Piezoelectric resonance is observed by measuring the dependence of the sample electrical impedance on the external electric field frequency. It is shown that inhomogeneous crystal heating can be characterized by the equivalent crystal temperature depending on the influence laser power. Equivalent crystal temperature can be directly determined from the measured piezoelectric resonance frequency.

Model of resonant acoustic spectroscopy of interaction of high power single-mode laser radiation with crystals

Every nonlinear optical laser frequency conversion process is accompanied by the crystal heating due to the absorption of some part of the radiation energy. Optical absorption coefficients and internal crystal temperature distribution during interaction with the high-power laser radiation are directly determined from modelling the experimentally obtained stationary and kinetics data of the radiation-induced frequency shifts of the crystal piezoelectric resonances.

Resonant acoustic spectroscopy of soft tissues using embedded magnetomotive nanotransducers and optical coherence tomography

We present a new method for performing dynamic elastography of soft tissue samples. By sensing nanoscale displacements with optical coherence tomography, a chirped, modulated force is applied to acquire the mechanical spectrum of a tissue sample within a few seconds. This modulated force is applied via magnetic nanoparticles, named ‘nanotransducers’, which are diffused into the tissue, and which contribute negligible inertia to the soft tissue mechanical system. Using this novel system, we observed that excised tissues exhibit mechanical resonance modes which are well described by a linear damped harmonic oscillator. Results are validated by using cylindrical tissue phantoms of agarose in which resonant frequencies (30–400 Hz) are consistent with longitudinal modes and the sample boundary conditions. We furthermore show that the Young's modulus can be computed from their measured resonance frequencies, analogous to resonant ultrasound spectroscopy for stiff material analysis. Using this new technique, named magnetomotive resonant acoustic spectroscopy (MRAS), we monitored the relative stiffening of an excised rat liver during a chemical fixation process.

Rapid evaluation of alkali–silica reactivity of aggregates using a nonlinear resonance spectroscopy technique

A new nonlinear acoustic technique — Nonlinear Impact Resonance Acoustic Spectroscopy (NIRAS) — is developed and used to characterize the alkali-reactivity of different aggregates. Cementitious materials such as mortar and concrete exhibit a hysteretic and nonlinear elastic behavior in their constitutive relations. This hysteretic nonlinearity is associated with interfacial debonding between the different constituents, and it changes with the progress of damage such as that induced by the alkali–silica reaction (ASR). One of the consequences of the hysteretic nonlinear property of these materials is the decrease in resonance frequencies, with increased excitation amplitude. This shift in the resonance frequency as a function of the material nonlinearity parameter can be used to directly characterize the damage state of the material. This research tracks the variation of the nonlinearity parameter during a standard accelerated mortar bar test (AMBT) to assess the potential for alkali-reactivity of aggregates. The results show that the NIRAS technique is more sensitive than conventional linear acoustic methods and is capable of accurately characterizing the reactivity of the aggregates examined. Furthermore, the results show advantages over standard expansion measurements for differentiating various aggregates having similar levels of reactivity, particularly at early test ages. These changes in the nonlinearity parameter are benchmarked against results from a petrographic analysis. Thus, the proposed NIRAS is a promising technique for the rapid identification of alkali-reactive aggregates.

Resonant acoustic spectroscopy of soft tissues using embedded magnetomotive nanotransducers and optical coherence tomography

Resonant acoustic spectroscopy of soft tissues using embedded magnetomotive nanotransducers and optical coherence tomography

Measurement of the coating thickness on the back side of double-sided coated structures by means of acoustic resonant spectroscopy

Abstract This paper describes a technique for measuring the thickness of the back side coating of a double-sided coated structure using acoustic resonance. The technique is used to observe the resonant frequency of high frequency ultrasound for a steel/coating/air structure. The resonant frequency of the transmitted ultrasound occurs when a quarter wavelength corresponds to the thickness of the back side coating, and the reflection coefficient has a minimum value. The top surfaces of the samples are covered with a coating about 30 μm thick and the thickness of the back side coating is in the range of 10.3–17.5 μm. The resonant frequencies for the examined samples are observed in the frequency range of 46.8–75.6 MHz, and the thickness of the back side coating can be accurately determined from the measured resonant frequency. Note that the coating on the top surface of the structure does not affect the thickness measurement accuracy of the back side coating.

Reconstruction of the Green function in problems of resonance acoustic spectroscopy

A possibility for reconstruction of the Green function for a three-dimensional elastic body (resonator) is considered. The initial data are the elasticity tensor for the resonator material that is measured by the technique of resonance acoustic spectroscopy and its complex vibration response. Possibility for the response reconstruction and determination of the coordinates for a force source of vibration excitation according to the measured data is demonstrated. The difference between the measured and synthesized responses is small that provides an opportunity to perform continuous calibration of acoustic measurements and determine the distribution of stress and strain within a solid.